Rotary hydraulic couplings



Sept. 20, 1960 E. KLUGE ROTARY HYDRAULIC couRLINGs 4 Sheets-Sheet lFiled Dec. 17, 1956 Sept. 20, 1960 E. KLUGE ROTARY HYDRAULIC COUPLINGS 4Sheets-Sheet 2 Filed Dec. 17, 1956 Sept- 20, 1960 E. KLUGE 2,952,977

ROTARY HYDRAULIC COUFLINGS Filed Deo. 17, 1956 4 Sheets-Sheet 3 ATTORNEYROTARY HYDRAULIC COUFLINGS Filed Deo. 17, 1956 4 Sheets-Sheet 4 X09 /07//7 ZZ/ INVENTOR BY @Mgg/gg ATTORNEY United States, Patent @hice2,952,977 norARY HYDRAULIC coUPLlNGs Eneval Kluge, 117 9- White BearAve., St. Paul, Minn.

Filed Dec. 17, 1956, Ser. No. 628,768

13 Claims. (CIV. 60-54) This invention relates to an improvement inrotary 'hydraulic couplings and deals particularly with a'variable speedcoupling which tends to maintain a constant adjusted speed.

An object of the present invention resides in the provision of a rotaryhydraulic coupling which includes a drive member to which is secured arotatable hub. A series of vanes are pivotally supportedintermediatetheir ends to this hub. These vanes are so constructed andarranged that in completely retracted position they provide acylindrical surface. In their other extreme position, the vanes extendoutwardly in a generally radial direction from the center of the hub. lThe hub and its vanes are rotatably supported in a chamber havinginternally extending tins. This casing or housing is rotatably supportedand is connected to the driven member. When the chamber is filled withhydraulic fluid and the vanes are fully retracted, they pro vide acylindrical structure which may rotate within the fluid with littletendency to rotate the housing. As the vanes are pivoted to swingoutwardly from the hub, they provide an everkincreasing force tending tomove the housing with the hub.

A feature of the present invention resides in the provision of acoupling of the type described Vincluding vanes which are pivotallysupported on axes which are generally parallel to the axis of rotationof the supporting hub.

The inner end of each vane is heavily weighted. Thus, during therotation of the hub, centrifugal force tends to swing the vanes towardclosed or retracted position. In the event the force against the vanesincreases, the centrifugal force acting upon the weighted ends of thevanes is overbalanced, tending to cause the vanes to -project a greaterdistance from the hub.

A further feature of the present invention resides in the provision of arotary coupling' of the type described, including a manually operablemeans for adjusting the position of the vanes Within the housing. Thismanually operable means includes a lost motion mechanism which permitssome adjustment of the vanes independently o'f the manually operablecontrol mechanism. As a result, if the load of the driven memberincreases, and the speed of rotation of the drive member is decreased toan extent where the centrifugal force upon the vanes decreases to apredetermined extent, the vanes may automatically project outwardly to agreater extent, thus providing a greater tendency to rotate the housingin unison with the hub. In a similar manner if the speed of rotationtends to increase, it also increases the force tending to retract thevanes.

A feature of the present invention resides in the provision of ahydraulic coupling which includes a series of pivotally supported vanesmounted upon a hub and in which the vanes are so shaped to provide aseal between the inner portion of the hub and the vanes at all times.The surface of the vanes is at all times in substantial surface contactwith the hub regardless of the .pivotal position thereof.

Patented sepewao, 19,60;

A further feature of the present invention resides in the provision of anovel means for projecting and retracting the vanes. An arm is connectedto each vane and to an axially slidable support. By moving the axiallyslidable support in an axial direction, the arms act to swing the freeends of the vanes from one extreme position to the other. Means Varealso provided for compensating for changes in angularity between thepoints of connection of the arms with the vanes and the slidablesupport.

These and other objects and novel features of the present invention willbe more clearly and fully setforth in the following specification andclaims.

In the drawings forming a part of the specification; p p

Figure l is a longitudinal sectional View through the rotary hydrauliccoupling and the control therefore.

Figure 2 is taken on the irregular section line 2- -2 of Figure l. Y

Figure 3 is a view similar to Figure 2 on a somewhat reduced scaleshowing the vanes in a different rotative position. Y

Figure 4 is a diagrammatic View of the hub and, lthe vanes, the viewshowing the vanes in contracted position in full lines and in projectedposition in dotted outline. Figure 5 is a View of one of the vanesremoved from the remaining structure, the View indicating the Vmanner inwhich the vane operating rods are connected to the vanes. Y Figure 6 isan elevation View of a detail portion of the apparatus removed from theremaining structure.

Figure 7 is a sectional View on the line 7 7 of Figure 6. Y

Figure 8 is a sectional view through a portion of the control mechanism,the position of the section being indicated by the line 8 8 of Figure l.v

Figure 9 is a detail portion of the control mechanism removed from theremainder of the construction.

Figure lO is an end View of the control mechanism. Figure 11 is anotherdetail portion of the control mechanism.

Figure l2 is a perspective view of one of the vanes detached from theremainder of the construction.

Figure 13 is a side elevational View of the coupling mounted for atypical use.

Figure 14 is an end elevation view of the arrangement shown in Figure13.

The rotary hydraulic coupling is indicated in general by the letter A.The coupling includes two main sections, one of which comprises thehydraulic coupling body and which is indicated in general by the numeral16. The other main part or section of the apparatus includes'the controlapparatus and this is indicated in general, by the numeral 11.

The coupling body The coupling body 10 includes a drive shaft 12 havinga slightly tapered socket 13 in its extremity. A sleeve 14 having akeyway 15 therein is provided with a tapered outer surface engaged inthe socket 13 and includes an enlarged diameter externally threaded endportion 16. The outer end of the shaft 12 is also externally threadedwith a left hand thread and a sleeve or collar 17 is threaded onto thesleeve portion 16 and the shaft 12 to hold these parts together. Thesleeve is right hand threaded and left hand threaded, so that rotationofthe sleeve is one direction draws the sleeve farther into the socket.As the keyway 15 forms a split in this sleeve, the sleeve may be wedgedagainst a drive shaft inserted into the sleeve, to center this insertedshaft -in the shaft 112.

A disc like body portion 19 is attached tothe shaft 12, this discactually forming a part of the hub. The

the hub 20 actually forming an extension of the shaft 3 s 12. 'Ihe hubor shaft portion20 is internally socketed asindicated at 21, the socket21 extending axially into Y Ythe shaft portion 20 from the opposite endthereof from olmeans of the coupling. Obviously, a gear, sprocket orother take-olf means can be substituted for the pul- Y ley 26.V

The hub 22 is connected by a laterally offset portion 27 to a disc-likeplate 29 which forms one side of the fluid housing, the housing beingindicated in general by the numeral 30. The offset portion 27 ispreferably stepped as indicated at 31 to fit with a running t about thedisc portion 19 on the drive shaft 12. Cooling ribs such as 32 arepreferably provided on the outer surface of the disc member 29, thesecooling ribs preferably extending radially outwardly from the offsetportion 27. The disc-like portion 29 supports an integral hollowcylindrical sleeve 33 which extends in concentric rela- 4 limitrotation. When the vanes are in fully projected position, the curvedsurfaces 55 of the vanes engage against the surface of the hub 20. Thus,these surfaces 54 and 55 limit the pivotal movement of the vanes abouttheir respective pivots 49.

As indicated in Figure 12 of the drawings, one end 56 of each vane 46 isilat and from Figures 3 and 4 of the drawings it will be noted that theat ends 56 extend on substantially radial planes through the axis of theshaft when in fully projected position. As is also eviden-t from Figure4 ofthe drawings, the dat ends 56 of the blades 46 engage in surfacecontact with the opposite end 57 of an adjoiningblade vwhen the vanesare in fully retractedposition. .The-outer surface S9 of each vanebetween the ends 56 and 57 thereof lies on a cylindrical surfaceconcentric with the hub 20 when the vanes are in fully retractedposition. Stated otherwise, the vanes 46 are designed to engage in endto end relation when the vanes are retracted to provide a cylindricalcontinuous outer surface in this position of the vanes. Y Y

As is indicated in Figure l2 of the drawings, the body of each vane 46is hollowon one side of the pivot aperture 47 so that this end ofeach'vane is extremely tion to the hub or shaft portion 20 forming apart of the drive shaft 12 and encircling this hub 20.' The fluidchamber is completed by a disc-like closure plate k34 which is connectedto a generally conical portion 35 vwhich terminates in a hub 36encircling the extended end 37 of the hub or shaft portion 20. Ananti-friction bearing 39 encircles the shaft portion 37 to provideV ameans of permitting relative rotation between the shaft and the fluidchamber. A seal 40 is also provided in the groove 41 in the innersurface of the hub 36 to preven the leakage of fluid from the uidchamber. f

.The closure plate V34V is connected to the disc-like closure 29 bymeans of bolts 42 or other suitable means.

VThese bolts 42 are arranged in angularly spaced relation about theperiphery of the fluid chamber as is indicated in Figure 2 of thedrawings. Y V

Angularly spaced fins 43 are provided on the inner surface of thedisc-like closure member V29 and extend in a generally radialdirection.Y Fins 44 are alsoY provided on the inner surface ofthersleeve 33, the fins 44 forming an extension of the iins 43. VFins 4Sare also provided on the inner surface of the closure plate 34, thefins-45 being arranged to extend in-a generally radial direction. Thesefins are designed to act somewhat in the capacity of the blades of laturbine and cause the fluid chamber to rotate with the hub 20 in theoperation of the coupling in a manner which will be later described indetail.

A series of angularly spaced vanes indicated in general by the numeral46 `are pivotally connected to the disc 19 to encircle the hub 20. Thesevanes are shaped as is best illustrated in Figure 12 of the drawings.The

vanes 46 include a pivot opening 47 designed to accommodate pivot bolts49 which extend through angularly spaced apertures 50 in the disc 19.The pivot-bolts 49 extend in a direction parallel to'the axis of theshaft portion 20 and include a head 51 which engages the vanes to holdthe same in place. 'I'he bolts 49 are held in place by suitable nuts 52which are located in recesses `in the disc 19. Y

'I'he vanes 46 are provided with arcuate portions 53 having the axis ofthe pivot aperture 47 as their center of arcuation. Oppositely curvedsurfaces 54 and 55 are provided on opposite sides of the curved portion53, these oppositely curved portions being of substantially the sameradius of curvature as the hub 20. With reference to Figure 4'of Y.thedrawings, it will be seen vthat when the vanes 46 are4 in fully.retracted position, thecrved surface 54 'engages .against .thel 1ub-20Vto 'relation to the shaft portion 37 light in Weight. Theportion 60 ofeach vane adjoining the end 57 thereof is formed Yof a materialsubstantially heavier than the remainder of the vane. In other words, ifthe vanes 46 Yare made of a lightweight vmaterial such as magnesium orthe like the other end 60 of each vane may be formed by a relativelyheavy metal such as lead or the like. As'is indicated in Figure l of thedrawings, semispherical sockets 58 are cast into the hollow interior ofeach vane. As is indicated in Figure 5 of the drawings, aninternally'threaded cylindrical passage 62 leads into the socket 58. VAnoperating arm 63 having a ball head 64 is engaged in each socket 58 anda threaded plug 65 is threaded into the passage 62 to engage' againstthe ball 64 and to hold the4 ball in place in the socket. Preferably theinner end of the plug 62 s concave to t the curvature of the ball 64 toprovide the operating arm 63 with a suitable socket so that it canYchange angularity relative to the connected vane.

The control mechanism The control mechanism "11 includes a sleeve 66which encircles the drive shaft portion 37. Anti-friction bearings 67and 69 are provided within the sleeve 66 and encircling the shaftportion 37 to provide relative rotation between these parts. A'seal 70is preferably provided outwardly of the hub 36. A spacing sleeve 71 isprovided between thebearings 67 and'69. A nut 72 is provided on theexternally threaded end of the shaft portion 37 to hold the bearings 67and 69 in proper The outer race of the bearings 69 engages against aninternally projecting ange 73 integral with the sleeve 66 and a spacingsleeve 74 is provided between the'outer races ofthe bearings 67 Vand 69.A radially extending lubrication passage 75 closed by a plug 76 or othersuitable means provides a way of lubricating the bearings when it isdesired.

A shaft 77 is slideably supported in the socket 21 extending into theshaft portion 37 and the hub 20. An

annular groove 79 in the shaft 77 supports a seal 78 between the shaft77 and the shaft portion 37 The portion Vwhich Vencircles a portion ofthe shaft portion 37 and the hub 20. As a result of this arrangement,the flange 84 on the sleeve 85 mayy slide longitudinally of the hub 20and may rotate to some extent relative to the hub 20 fo a purpose whichwill be later described. The limits of this relative rotation is definedby the longitudinal edges of the apertures 80 on opposite sides of theshaft portion 37.

As shown in Figure 1 of the drawings, the connecting or operating arms63 are provided with enlarged ends 89 having pivot apertures 90extending therethrough. These enlraged ends 89 are provided withparallel sides which engage between the flat sides of the radial grooves92 arranged in angularly spaced relation in the flange 84. Pivots 93(Figure 2) pivotally support the `arms 63 and connect these arms formovement withA the ange 84 and slideable sleeve 85. A `piston 94 isslideably supported within the sleeve 66 and includes a ring shaped body95 having an inwardly extending ange 96 which engages against a shoulder9 7 on the shaft portion 77. A bearing 99 is interposed between the ange96 Aand spacing washers 100, these washers being held in place by a nut101. 'Ihus the piston may rotate relative to the shaft 77 but moveslongitudinally in unison therewith.

As is best illustrated in Figure 11 of the drawings, the piston 94 isprovided with a groove 102 which extends along a chord of thecylindrical outer surface of the piston, the groove having its sideedges parallel with the ends 103 and 104 of the piston. A slide 105 isprovided in the groove 102, the slide 105 having a cylindrical pivotopening 106 therein extending normal to the base of the groove 102. Thisaperture 106 is designed to accommodate an eccentric pin 107 mounted onthe cam 109 which is shown in Figure 8 as being pinned at 110 to a shaft111. Rotation of the cam 109 thus acts to reciprocate the piston 94axially, the slide 105 moving in the groove 102.

As is indicated in Figure 8 of the drawings, the shaft 111 extendsthrough the plug 112 mounted in a tubular portion 113 of the casting 114forming the enclosure for the control mechanism. As is indicated inFigure l of the drawings, the casting 114 includes two right angularlyextending tubular portions 66 and 113 the axes of which intersect. Thecasting also includes a pair of lugs or brackets 115 and 116 throughwhich the operating shaft 117 extends for support.

The shaft 111 is supported by bearings `119 and 119. The end portion ofthe plug 112 includes a reduced-diameter sleeve element 120 which servesas a bearing for the hub 121 of a gear 122. 'Ihe shaft 117 vis parallel`to the shaft 111 and a gear 123 has its hub 124 mounted upon the shaft117 for rotation in unison therewith. Rotation of the operating shaft117 thus acts through the gear 123 to rotate the meshing gear 122.

As is indicated in Figure of the drawings, taken in conjunction withFigure 8, a disc 124 has its hub 125 keyed to the shaft 11 as indicatedat I126. The disc 124 is provided with a pair of diametrically :opposednotches 127. Pins 129 are mounted in the gear 122 and project into thenotches 127. As the notches are substantially wider than the diameter ofthe pins 129, the disc 124 may rotate angularly for some distancerelative to the gear 122. This provides a lost motion arrangement whichassists in the operation of the construction as will be described.

Operation of the coupling The coupling is mounted in a suitableposition. A power shaft is inserted Within the sleeve 14 and the sleevewedged between this power shaft and the drive shaft 12. The pulley 26 isattached to a driven member which is to be driven at a variable speed.

By rotation of the control operating shaft 117, rotation may betransmitted through the gears ,-123 and 122 to the parallel shaft 111through the disc 124. Rotation of the gear 122 brings the pin or pins129 to one end of the slot 127 and further rotative movement of the gearin the same direction will act through the disc to rotate 6 the shaft111 and the eccentric disc 109 attached thereto.

Rotation of the eccentric disc 109 acts through the pin 107 and itsbearing 105 to move the piston 94 longitudinally of the cylinder inwhich it is positioned. Longitudinal movement `of the piston 94 movesthe driven shaft 77 longitudinally within the axial socket of .the hub20 and its driven shaft extension 37.

Movement of the rod or shaft 77 in one direction acts to move the sleevewhich is connected by the arms 63 to the various vanes 46. Thus,movement of the member 77 in one direction acts to swing the vanes 46toward retracted position so that the outline of the vanes forms acylindrical surface. Accordingly, when the shaft or rod 7 7 is in itsoutermost position, the vanes are fully retracted and rotation of thehub 20 and the vanes will cause insuthcient movement of the fluid withinthe fluid chamber' to move the housing 30 in unison with the vanes.

Rotation of the control rod 117 in the opposite direc* tion acts throughthe lost motion mechanism described to move the sleeve 85 inwardly.'Ihis motion acts through the rod 63 to urge the hollow ends of thevanes outwardly. As the vanes move outwardly, they create a forceagainst the liquid within the housing 30 tending to rotate this body ofliquid with the vanes, The moving liquid acts against the internal ribsin the casing 30 to rotate the housing or casing. If the vanes are butslightly projected, the housing will rotate at a relatively low speed.As the ends of the vanes are projected a greater amount, the tendencyfor the liquid in the casing to rotate the casing increases, until whenthe vanes are virtually fully projected, the casing will rotate atalmost the same speed as the drive shaft.

From the foregoing description it will be seen that a variable speeddrive is provided which can rotate the driven member at a desired speed,and this speed may be regulated by operation of the control mechanism.If the load upon the driven member remains substantially constant, thelost motion mechanism which has been described has little effect uponthe operation.

It will be seen that as the vanes rotate, the force of liquid againstthe operating or outer ends of these vanes tends to swing the vanestoward fully projected position. At the same time, centrifugal forceacting upon the weighted opposite or inner ends of the vanes tends toswing the vanes toward a closed or retracted position.

In the event the driven member is operating at a predetermined desiredrate of speed and a heavy load is suddenly applied -to the drivenmember, this load tends to hold the driven member Vand casing fromrotation. The reduction in speed-of the outer casing imposes a greaterforce upon the outer or projecting ends of the vanes. When this force issufficient, the vanes are permitted to move outwardly by the lost motionmechanism previously described. In Vother words this pressure acts uponthe connecting rods 63 to move the shaft or rod 77 inwardly, this motionacting through the eccentric to rotate `the shaft 111 through theangular distance necessary to move the pin 129 from one end of the slot127 to the opposite end thereof. By increasing the extent of projectionof the vanes, these vanes will exert a greater force against the liquidin the housing 30 until the housing again rotates at the desired speed.When the pulley attains the proper speed, the force upon the vanesdecreases and the centrifugal -force on the weighted ends of the vanestends to retract these vanes. In other words, when the driven member isadjusted to rotate at a desired speed, the vanes are not rigidly held ata predetermined degree of projection from their hub and there is at alltimes a balance between the lcentrifugal force acting on one end of eachvane and the uid pressure acting upon the other end thereof. When theload upon the driven member lessens,-the effect of centrfiugal forceoverbalances the force acting upon the vanes, acting to retract thevanes within the limits of the lost motion mechanism. As a result,during operation, the pin 129 of the lost motion mechanism merely oatsbetween its two extreme positions moving in one direction when the loadfon the driven member'increases and moving in the opposite directionwhen the load on the driven member decreases.

In accomplishing the result described, a careful balance between theweighted ends of the vanes and the hollow outer or projecting ends ofthe vanes is necessary.

However, in actual practice it has been found that when a load isapplied to the driven member, the lost motion mechanism will quicklycorrect any variation in speed of the driven member by projecting thevanes to a greater extent. As theY load eases oi, the lost motionmechanism acts to retract the blades to some extent due to thecounterbalancing effect of the weighted ends of the vanes therebyproviding a variable speed mechanism which functions effectively for itsintended purposes. g

Manner ofrmozmling The manner of mounting the clutch mayA be variedWithin'substantial limits. In Figures-713 and 14 is a typical mountingarrangement is shown. A ring 132 having holes 133 in angularly spacedrelation therethrough is supportedV by arms 134 to a fixed platform V135forming a part of the frame 136. The coupling A is driven by a motor 131on the frame 136. The coupling is connected by belts 139 to a countershaft 130, to drive this shaft.V Y

The control shaft 1'17 extends through an arm 140 having an internallythreadedA axial socket to accommodate a thumb screw 141. This thumbscrew may hold the shaft 117 in any angular position, so'that theadjustment may vary through 360 degrees.Y In this way the operating'handle may be positioned to suit the convenience of the Jperator. Y l Yi The clutch is enclosed within an outer shell 143 includ- 'ing a disc1,44 secured to the sleeve 66 by bolts 145 and also including acylindrical sleeve 146V connected at one end to said disc and encirclingthe housing. The disc 144 is provided with angularly spaced yapertures147- therethrough spaced from the periphery thereof. The other end ofthe sleeve 146 is open. Rotation of the housing withinthe shell acts todraw air through the apertures 147 and force Vair through Vthe open endof the shell sleeve 146. Y f

Due to the fact that theV sleeve 66 is rotatable relative to the drivenshaft and the driven housing, some means must be provided for holdingthe sleeve 66 from rotation. By providing the ringY 132 adjacent thecontro1 Y shaft Y117, and connecting the arm 140 encircling the controlshaft to the ring, the shaft 117 may be secured to trifugal force actingupon the weighted ends of said vanes tending to counter balance theforce of hydraulic fluid against therprojectable ends of thevanes, meansfor simultaneously pivoting said vanes toward projected or retractedposition, fand lostV motion means in said vane pivoting means, said lostmotion means permitting some variationV in the projection of saidvanesrat a predetermined position of a portion of said Yva'ne pivotingmeans whereby an increase in the load resisting rotationof said housingtends to project said vanes and a reduction in load resisting rotationYof said 'housing tends Yto retract said extend in any direction. Theentire control, including the Y Y sleeve 66 and shell 143 may be pivotedabout the axes of the drive shaft and housing when these elements arenot in operation. l

In accordance with the patent statutes,` I have described the principlesof construction and operation of my improvement in rotary hydrauliccouplings, and while I have endeavored to set forth the best embodimentthereof, I desire to have it understood that changes V.may be madewithin the scope of the following claims without departing from thespirit of my invention.

I claim: Y

1. A rotary hydraulic coupling including a drive shaft, a housingencircling a portion of said drive shaft and o being relativelyrotatable with respect thereto, a series of vanes within said housing,pivot means pivotally con-Y may be'forcedV against Vsaid fins byjsaidyaneathe .Ceu- P vanes.

2. The construction described in claim 1 and in which said vanes areangularly spaced about said drive shaft and arershaped to provide acylindrical outer surface in fully retracted position. i i i i .v

3. A variable speed device including a rotatable drive member, a coaxialrelatively rotatable driven member, one of said members including anouter rotatable housing havingspaced sides and a connecting peripheralsleeve connectingsaid sides, theV other of said members including Ya hubextending within said housing, vanes supported on said hub to extendkoutwardly therefrom vwithin said housing, means pivotally supportingsaid vanes,rmeans connecting said vanes for pivoting the same in unison,a control connected to said connecting means to Iactuate the same, saidcontrol being pivotal relative'to said drive member and said drivenmember about the axis thereof when said drive member and driven memberare Vstationary, an outer shell spaced from and encircling said housingand connected to said control'and pivotal in unison therewith, saidshell including a disc having angularly spaced apertures therethroughVspaced from the periphery thereof and, said shell also includingacylindrical sleeve connected atone end to said disc and encircling saidhousing, said sleeve having Van open end opposite the end thereofconnected to said disc, whereby rotation of said housing within saidshell will act to draw air through said apertures and force air throughsaid open end of said shell sleeve. i i

4. The structure of claim 3 and in which said means connecting saidvanesris movable in a directionaxially of said drive and driven members.i

5. A rotary hydraulic coupling including ardrive shaft, a rotary housingencircling said drive shaft, internal ribs on the interior of saidhousing, a series of vanes pivotally Vconnected to said drive shaft onaxes substantially parallel to the axis of said drive shaft, ksaid vanesbeing pivoted intermediate their ends and having inner endssubstantially sealed relative to said drive shaft, said vanes, in oneextreme position, forming `a rotor having a substantially continuouscylindrical .outer surface, an arm pivotally connected to each vane forcontrolling the pivotal position thereof, an axiallyY movable controlmember to which each said arm is connected for movement, meansexternally of said housing connected to said axially movable member formoving the same, lthe innerV ends of said vanes being weighted,whilerthe outer vane ends are relatively light, wherebythe action ofcentrifugal force tends to urge the vanes toward retracted position.

6.V A rotary hydraulic coupling-including a drive shaft, a rotaryhousing encircling said Vdrive shaft, internal ribs on the interior ofsaid housing, a series of vanes Ypivotally connected tol said driveshaft on axes substantially parallel to the axis of saidrdrive shaft,said vanes being pivoted intermediate their ends and ha'yingy inner endssubstantially sealed relative to said` driveV shaft, said are relativelylight, so that the action of centrifugal force .tends to urge the vanestoward retracted position, and including a lost motion mechanism betweensaid arms and said means externally of said housing.

7. A rotary hydraulic coupling including a drive shaft having acylindrical outer surface, a fluid containing rotary housing encirclingsaid drive shaft, internal ribs on the interior of said housing, aseries of vanes pivotally connected to said drive shaft on axessubstantially parallel to the axis of said drive shaft, said vanes beingpivoted intermediate their ends and having inner ends including arcuateportions substantially sealed relative to the cylindrical outer surfaceof said drive shaft regardless of the pivotal position thereof, saidvanes each having an arcuate side, the center of arcuation of said sidesbeing at a common point when said vanes are in one extreme position toprovide a continuous substantially cylindrical outer surface, a atportion of the inner end of each vane abutting against a flat portion ofthe outer end of the next adjacent Vane in said one extreme position,said vanes having substantially at ends extending in substantiallyradial planes through the shaft axis in their other extreme positionsand means connecting said vanes for operation in unison.

8. The structure of claim 7 and in which said vanes are so shaped andsupported that reaction of iiuid against the vanes caused by rotation ofthe vanes tends to pivot the vanes toward the other extreme position,and in which the inner ends of said vanes are weighted, wherebycentrifugal force tends to urge said vanes toward said one extremeposition.

9. A rotary hydraulic coupling including a drive shaft, a uid containinghousing encircling said drive shaft, internal ribs on the interior ofsaid housing, a series of vanes, means pivotally connecting said vanesto said drive shaft on angularly spaced axes about, and parallel to saiddrive shaft, said vanes being pivotal between two extreme positions,said vanes being substantially sealed relative to said shaft in allpositions, means for pivoting said vanes in unison, said vanes havingone substantially at end projecting on a substantially radial planethrough the shaft axis outwardly from said shaft in one extremeposition, the ends of said vanes abutting in the other extreme positionthereof, said vanes having an arcuate outer surface forming asubstantially continuous cylindrical surface in said other extremeposition of said vanes, said other ends engaging said shaft in said oneextreme position to limit pivotal movement thereof.

10. The structure of claim 9 and in which each said vane includes aninner arcuate surface in tangential relation to said shaft and formingthe seal between each vane and said shaft.

ll. A rotary hydraulic coupling including a drive shaft, a housingencircling a portion of said drive shaft and being relatively rotatablewith respect thereto, a series of vanes Within said housing, pivot meanspivotally connecting said vanes to said shaft for rotation in unisontherewith, the axes of said pivots extending substantially parallel tothe axis of said drive shaft, said pivots extending through said vanesintermediate the ends thereof, said vanes having outer projectable endsand inner weighted ends, said weighted ends being substantially heavierthan said outer projectable ends, said housing having internal tins andincluding hydraulic fluid which may be forced against said tins by saidvanes, the centrifugal force acting upon the weighted ends of said vanestending to counter balance the force of hydraulic iluid against theprojectable ends of the vanes, means for simultaneously pivoting saidvanes toward projected or retracted position, whereby an increase in theload resisting rotation of said housing tends to project said vanes anda reduction in load resisting rotation of said housing tends to retractsaid vanes.

12. The structure of claim 11 and in which the inner weighted ends aresubstantially sealed relative to said drive shaft.

13. The structure of claim 11 and in which said outer projectable endson said vanes are provided with surfaces on planes substantially throughthe axis of the drive shaft in projected position.

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